On nonlinear systems diagnosis using differential and algebraic methods

In this paper we tackle the diagnosis problem in nonlinear systems under failure using differential algebra. Three examples are presented in order to apply the proposed methodology. Numerical simulations of these examples are presented to illustrate the effectiveness of the suggested approach.     

高水平乒乓球运动员有力臂最大等长收缩力的评估

乒乓球是使用单侧上肢的一项运动,其特征是要进行重复多次高速且具爆发力的动作,无氧乳酸酵解代谢能力占有重要作用.研究对象与方法男女高水平乒乓球运动员(n=31).采用Takei5101握力计测量单侧上肢有力型和非单侧上肢有力型运动员的上肢最大等长收缩力.18名男运动员(平均年龄23.5±5.4岁)和13名女运动员(平均年龄21.3±3.3岁)均为西班牙乒乓球协会的国家联盟成员.采用SPSS v12.0 for windows和Excel v10.2软件包进行数据统计分析.研究结果发现无论男女运动员单侧上肢有力型的最大等长收缩力均高于非单侧上肢有力型,而左势手女运动员与右势手女运动员相比、右势手男运动员与左势手男运动员相比,单侧上肢有力型的最大等长收缩力均高于非单侧上肢有力型.研究还发现进攻型运动员与防守型运动员相比,单侧上肢有力型的最大等长收缩力高于非单侧上肢有力型.分析与讨论无论男女,单侧上肢有力型运动员手握力高于非单侧上肢有力型运动员.男性运动员比女性运动员的等长收缩力高,一个可以解释的事实是男性有更高的睾酮水平.肌肉力量不平衡可能发展成为脊柱侧弯姿态,这应该通过适当的力量和柔韧性训练来避免,以防止将来的运动损伤和运动成绩的下降.     

POSTCOLLEGE EARNINGS OF FORMER STUDENTS OF CALIFORNIA COMMUNITY COLLEGES: Methods, Analysis, and Implications

In the wake of new federal and state mandates,community colleges are faced with demands to provideaccountability reports on student outcomes. With the useof the Employment Development Department Unemployment Insurance (EDD-UI) wage record data, along withthe California Community Colleges Chancellor's OfficeManagement Information System administrative database,this study sought to investigate the extent to which completing an associate degree andvocational certificate impacts the postcollege earningsof students. Based on information from 700,564 studentsfrom California community colleges during the 1992-93 academic year, the findings suggest thatstudents' gains from first year out of college to thirdyear out will differ by age group. Among economicallydisadvantaged students, a strong positive relationship exists between educational attainment andpostcollege gains. An important finding among vocationalstudents is that as women complete more education, theearnings gap closes between men and women. Finally, this study raises several policy implicationsand presents suggestions for future research.     

A simple and efficient device for demonstrating cross‐sectional anatomy of the head

Described in this article is a novel device that facilitates study of the cross‐sectional anatomy of the human head. In designing our device, we aimed to protect sections of the head from the destructive action of handling during anatomy laboratory while also ensuring excellent visualization of the anatomic structures. We used an electric saw to create 15‐mm sections of three cadaver heads in the three traditional anatomic planes and inserted each section into a thin, perforated display box made of transparent acrylic material. The thin display boxes with head sections are kept in anatomical order in a larger transparent acrylic storage box containing formaldehyde solution, which preserves the specimens but also permits direct observation of the structures and their anatomic relationships to each other. This box‐within‐box design allows students to easily view sections of a head in its anatomical position as well as to examine internal structures by manipulating individual display boxes without altering the integrity of the preparations. This methodology for demonstrating cross‐section anatomy allows efficient use of cadaveric material and technician time while also giving learners the best possible handling and visualization of complex anatomic structures. Our approach to teaching cross‐sectional anatomy of the head can be applied to any part of human body, and the value of our device design will only increase as more complicated understandings of cross‐sectional anatomy are required by advances and proliferation of imaging technology. Anat Sci Educ 2010. © 2010 American Association of Anatomists.     

Psychological Correlates of Fear of Falling in the Elderly

Fear of falling (FOF) is widely found in the elderly population and, regardless of its complex nature as a multicomponent construct, its related psychological variables have been overlooked as primary research topics. This article aims to examine the relationship between FOF, falls self efficacy, anxiety, balance, and perceived control over falling in a sample of older adults. A total of 100 subjects aged 60+ were asked about the presence of FOF, falls history, health, and functional status; they also completed the Falls Efficacy Scale (FES), the Geriatric Anxiety Inventory (GAI), the Perceived Control Over Falling Scale (PCOF), and the Performance-Oriented Assessment of Mobility and Balance (POMA-I). FOF was found to be associated with low falls self efficacy, low perceived control over falling, and reduced balance but not with anxiety. Conversely, a statistically significant association was found between GAI and FES, PCOF and POMA-I, and 47.1% of FOF was explained by two items from FES and GAI. FOF is influenced by variables that, though being commonly considered equivalent to FOF, do not fully explain it. A critical thought on the instruments used to evaluate FOF, is needed as well as additional studies to clarify the role of specific psychological variables.     

Pedagogical differences during a science and language intervention for English language learners

The purpose of this study was to compare and describe 8 fifth-grade classrooms by their teachers pedagogy during a quasiexperimental, longitudinal, and field-based project focused on increasing English language learners' (ELLs') achievement in science and language. The larger study found statistically significant and positive intervention effects in favor of the treatment group on measures of science and language achievement. This study adds an in-depth analysis of the teacher pedagogical practices contributing to students' science and language achievement as captured by an observational instrument used during the project. Results from the analysis show how treatment teachers, when compared to control teachers, focused on activities promoting verbal and written interaction among the students and dense cognitive language use during science inquiry instruction. The findings support the importance of effectively using language in the science classroom to improve ELLs' science and language achievement. Implications for future research and practice are discussed.     

Human capital background and the educational attainment of second-generation immigrants in France

In this paper, we study the impact of parental human capital background on ethnic educational gaps between second-generation immigrants using a large data set conducted in France in 2003. Estimates from censored random effect ordered Probit regressions show that the skills of immigrants explain in the most part, the ethnic educational gap between their children. Fluency in French and the length of their parents’ stay in France also matter. The impact of the immigrants’ education on the educational attainment of their children further depends on their country of origin, their place of schooling, and their proficiency in French.     

Interoperability and Information Integration in an Early Online Academic Digital Library of Theses and Dissertations: The Case of BTD

Cooperative organization has been proposed as a means to improve the usefulness of virtual libraries. Information interchange among library and other academic applications is often hindered by the lack of application interoperability. This hindrance may be overcome through the development of standards that allow for digital libraries to exchange and share information with other applications. The Graduate Program in Production Engineering (PPGEP) of the Federal University of Santa Catarina (UFSC) launched its Theses and Dissertations Bank (BTD) in 1995. BTD is possibly the first online academic digital library of theses. From a digital document repository, BTD evolved into a system that combines bibliometry and informetry features. BTD is used by students and faculty in their research activities, but also by decision makers from industry and academia. They use it, respectively, to search for specialists and to measure interest and knowledge interchange among PPGEP research areas. This article presents the history, features, and development prospects for the BTD project. The integration of BTD with other academic applications, especially those of the Brazilian national science and technology platform, is emphasized.